Paul system retrofit

Luv'nsteam

Anyone out there ever modify a one-pipe steam system to a Paul system?  How did you do it?  Where did you get the Paul valves and the Paul exhauster?  How did you run the vent lines from the radiator?  How/from where did you tap the steam main (or header?) to power the exhauster?



Thanks,

Mike

Steamhead

Not that I know of- yet

you thinking of doing one? 

Luv'nsteam

Paul system retrofit

Yes. 



Mike

Steamhead

Excellent!

We'll have to get Gerry Gill, Terry Tekushan, Boilerpro and a few others on here...... I'll work on that......

ttekushan_3

Paul vents, a pump, and a regulator.

My ears were burning, so I looked around the Wall and...



Thanks for the vote of confidence, Frank. I also know Gerry wants to fully restore a Paul type system.



Mike, I would forget about the steam powered pump capable of moving that volume of air out of the system. Use an electric one. It won't use that much power, especially considering the potential for fuel savings. I've heard of up to 30% fuel reductions, but I don't know how reliable that information is. IMO, if you got a 20% reduction that would be the minimum and quite delightful.



Some vacuum systems use a liquid ring pump, but it might not be a good choice in this application. It must be primed as these pumps are typically used in two pipe vacuum systems where they are necessarily pumping both condensate and air. When the pumped fluids rise above 140F the pump becomes less efficient. I'm thinking a vortex blower/vac might be a good choice for this particular application.



The ideal radiator vents are the Hoffman #3. Pricey but available. About $68 apiece if I recall correctly.



Regarding the depth of the vacuum, that is a much more complicated topic. You could merely set the vacuum level to a nominal level for evacuating air. This is fine and all you really need. But it would be interesting to be able to vary the vacuum level based on demand and outdoor temperature. The ancients were able to do so, but adapting modern controls to achieve the same goal might be too daunting. To really control steam temperature and volume, the vacuum must also communicate back to the supply to lower the system (supply and vent) below atmospheric pressure while maintaining a pressure differential to allow steam circulation regardless of their absolute pressure. There I go again, complexifying things before getting off the ground... Certainly its too daunting to start out with! We don't want to discourage this project!



Lets just stick to a fixed vacuum like a pound or two (2-3" Hg vacuum). It'll be a night and day difference.



Lets continue this. Perhaps Gerry can pipe up too ;-)



-Terry

Luv'nsteam

Terry & Steamhead,

thank you for the replies!  I was begging to think I asked for something impossible.



Anyway. Terry, per Dan in TLAOSH, page 250 (gold-cover edition), Dan states "The exhauster, being a steam jet, required no maintenance at all", a pump will.  A pump is not out of the realm of possibility, but  I prefer to duplicate what the Dead Men originally created.



Perhaps someone out there has an old, low-pressure exhauster they would like to sell??



Thank you,

Mike

Unknown

Let's not get stuck with old concepts.

I haven't read TLAOSH recently and I don't have my copy readily available to check, but as I remember didn't the exhauster run off the co generation steam engine?

Mike, with all respect to the "Deadmen", maybe it would better to see just what could be done with this system using all technology between the Deadman's time and 2009. The Deadmen were very progressive guys and went with cutting edge technology and I'm sure they would have taken this approach if they were still around.

I'm really interested in your project as I have a 1 pipe system and with the price of energy going up, I'm looking for ways to make it more efficient. 

- Rod

Luv'nsteam

lost in time

Rod, I agree with you...mostly.  I will entertain any suggestions utilizing new, old or hybrid technology.  



And yes, the steam usually came from an engine.  I believe it could be powered another way: from the steam main or perhaps directly off the header.  Maybe drill and tap the pipe or a cast fitting to create a new fitting to supply steam to power the exhauster.  I do not believe it will take a great deal of steam to do this, just simple, proven, reliable mechanical principles that still apply today and do not require electricity to operate.



I get the feeling their are several folks interested in my project.  I am very willing to share any and all things I discover, including photos, drawings, etc that make the project possible.



Thank you,

Mike

Unknown

Venturi

Hi Mike-  Thanks for the offer to share info.  As to the vacuum off the boiler - It would depend on the volume of vacuum that was needed. I have some experience in the plastics industry where  we used vacuum pumps for vacuum bagging composite laminates. For the smaller jobs one could use a vacuum venturi  which used a flow of compressed air to create a vacuum. I'm assuming that the "exauster" system was/is somewhat similar.  The volume and pressure of compressed air needed to operate the venturi was quite high (relative to a residential steam system) so while I can see it would work on a steam engine,  I'm wondering if this is practical on residential steam boiler.  Here's a link to a commonly used venturi:

http://www.jamestowndistributors.com/userportal/show_product.do?pid=3778



i suspect a venturi "exhauster" maybe a "deadend" and wanted to mention it so you don't waste time on trying to make it work. I 'd be really interested in what the Pros think about this. I don't have a real feel yet as to how much vacuum one would need or how to control things. Also does the system need to be evacuated BEFORE starting the boiler as this would mean an auxiliary vacuum pump. Just random thoughts.

- Rod

Luv'nsteam

steam-created vacuum

Rod, I am not an engineer.  However, I am familiar with your explanation of the venturi.  Also, this is what Dan says powered the exhauster.  He also states the Paul exhauster used a steam-jet with the venturi to create vacuum.  I found this on the net: http://www.graham-mfg.com/usr/pdf/TechLibVacuum/23.PDF  I did not read all of it yet, but it does say to pull steam off the header to create the vacuum with.



As for the Paul system, there were two exhausters: one for high pressure and one for low pressure.  Go here and scroll down to the next page (169) for a picture of each:  http://books.google.com/books?id=yj9GAAAAMAAJ&pg=PA168&lpg=PA168&dq=paul+system+exhauster+for+steam+heat&source=bl&ots=irt4-rot7F&sig=YYW2w0p4tfIhYEH5MJpIqhyWOis&hl=en&ei=GujgSublHsqLtgfvjaXcDA&sa=X&oi=book_result&ct=result&resnum=4&ved=0CBYQ6AEwAw#v=onepage&q=&f=false 



It is interesting to note, after reading the first link about the steam ejector and then looking closely at the low-pressure Paul exhasuter, I see two ejectors in that pic, what looks like condensate removal piping and maybe a diaphram or some kind of trap.  What do you see?



Thank you,

Mike

gerry gill

Were planning on restoring one this year.

If i can get the time to start it..weve done some vacuum testing at steves house on his mouat two pipe system..we fould that we can pull a decent pressure differential with a water venturi pump..it sucked on the return pipes and actually pulled the water right out of the mouat gauge..it was just 3 or 4 inches of water vacuum too..not mercury inches..we did try an electric vacuum pump and let it pull on the return..we found that we had 2'' mercury difference from the supply side to the return side..we also found that we had banging where none existed before..we therorized from where the banging was taking place that 2'' mercury was enough of a vacuum to hold condensate up in the riser to the second floor where then it got clobbered by the steam..so when we do the refurbishment of the paul system we are going to use a tank and an electric circulator that shoots water thru a mono flow tee and creates a vacuum in inches of water..another thing we found in our tests was that you don't really pull the steam..all that is done is to create a difference of pressure from the supply side to the paul line..picture putting a glass coke bottle in your mouth and sucking on it..you don't really ''move'' air..you just drag down the atmospheric pressure..not sure if i explained that well..but the steam doesn't rocket around like you would think..there is no ''wind'' in the pipe because the system is tight just like a coke bottle..but you should have guarenteed steam distribution because of the pressure difference..thats our thoughts anyways.

Unknown

Paul System

If one is designing a Paul system, what exactly is the goal of creating a vacuum? Is it just for better steam distribution or is there a benefit of trying to pursue lowering the boiling point of water?

Gerry- Thanks  for the info. Very interesting!

- Rod

gerry gill

The goal would be better distribution of steam

by creating a difference in pressure so the steam will go from high pressure to low pressure..but you'd have lower pressure everywhere so the steam should spread out better instead of just going into the radiators that are already condensing steam..there isn't that much benefit in attempting to lower the boiling point on a gas boiler as its just the sensible heat that will change..the latent heat needed to transform water to steam i think would stay the same..i'm not positive of that but i think so..and thats the big chuck of btus.

Patrick_North

Was this originally vacuum?

Was this system originally a vacuum system, or is the Paul system truly an add on?

Just curious. Followed this thread with interest- any new developments?

Patrick

Luv'nsteam

vacuum originally or not?

Yes, the system was originally a vacuum system.  A Trane vapor/vacuum system in fact, as evidenced by the the receiver in my basement identical to the drawing on page 257 (figure 37) in the TLAOSH.



BTW: I am not sure if I am converting to the Paul system this season or not.  Still undecided on the means of creating vacuum, although Dan suggested using an electric vacuum pump.  I think I am going to look into a steam ejector and see what kind of pressure is required to operate it in order to create about 5" of vacuum (Dan's suggested number).  If I can avoid the need for an additional source of energy (electricity) I will.



Thank you,

Mike

jumper

vacuum one pipe

Maybe fifty years ago in Toronto, I remember high rise buildings with "tight" steam systems.

By tight I mean the system held its vacuum indefinitely. Only periodically would maintenance pull vacuum right down to saturation with water powered venturii. Water was added manually and degassed first.



There was a stack of generous tanks. One to collect condensate; another to maintain water level. No vents,drips,traps, or boiler feed pump.



I believe the header was at top of building so steam & condensate were downflow parallel.

nicholas bonham-carter

Vacuum rules

Once again the subject of vacuum has risen. It's time to make this old method work.

As far as the Paul system retrofit, I think it should be combined with the the gill-iron-fireman- system fed through the air vent tapping, with a vacuum maintained from naturally induced vacuum.--NBC

Long Beach Ed

Paul Retrofit

We did one here on Long Island about eight years ago. 



Hoffman gave us a deal on the vents, and we made a vacuum pump using a Taco circulator and a bronze vacuum exhauster in bucket.  We had also tried an electric vacuum pump which also worked well but was noisy. 



We ran 1/4" copper through the basement and up the exposed steam risers. 



Our findings were similar to what is described here.  We produced a few inches of water vacuum and that was sufficient to aid distribution tremendously.  Steam reached the last radiator in the system in 30 seconds rather than ten minutes. 



We had no trouble with water hammer, but the system was a perfectly designed simple, well drained one pipe system in good condition. 



I also believe we could have down-sized the boiler somewhat, but we didn't test that. 



Overheating was initially a problem, but we balanced things to correct that.  We proposed zoning the system using two manifolds and zone valves.  Ideally, a zoned system could produce large savings.



The system ran for several years and was removed when the house sold.  Fuel savings were probably about 15% - 20%.

jumper

sealed vacuum vapor heating

Has anybody tried sealing all vents and pulling the vacuum from the header ?

With minimal noncondensibles and infiltration you accomplish a heat pipe heating system.

Al Corelli_2

Diagram for your Vacuum device?

Might you have a diagram for your vacuum device I could see?



This vacuum idea sounds great.

gerry gill

thats a great idea Ed..

i hadn't even considered the thought of being able to zone..very cool idea.

ChrisJ

heatpipe

Why wouldn't that work?



You could also set up a switch which fires up the vacuum pump whenever the vacuum drops to a certain level and the burner isn't firing.

Mark N

High pressure goes to low pressure

You want to pull the vacuum at the rads because high pressure goes to low pressure, and the place you want the steam is in the rads.

ChrisJ

Huh?

If I block all of my vents and pull a vacuum in the basement the entire system is going to have the same amount of vacuum with the boiler off. It doesn't matter where you pull it from.

Mark N

Vacuum

In a naturally induced vacuum system the condensing steam in the rad forms the vacuum pulling the steam to the rads. In a 2 pipe vacuum system the vacuum is pulled through the return. If you block the rad vents and the pressure is equal through out the system there is no differential to move the steam.

ChrisJ

Hmm

Mark,



I don't think I'm understanding how the systems work. I'm going to do some reading and see if I can grasp the entire concept.

Abracadabra

vacuum

But when the boiler starts a cycle, isn't the pressure near the boiler greater than the pressure at the radiators?  Isn't this the premise behind this: http://www.heatinghelp.com/files/articles/1310/128.pdf

gerry gill

in a steam system

the steam pressure is never the same in two places, and if a vacuum is being pulled by a mechanical device its vacuum is also not the same in two places.

Mike Kusiak_2

Vents and vacuum

If you had a perfect vacuum in the system, there would be no need for vents. The reason for the vents is to release air from the system and allow steam to enter. With a perfect vacuum, by definition there is no air and therefore the vents serve no purpose.



So say we have an ideal vacuum and the boiler is cold. The vapor pressure of the system is in equilibrium and with no pressure differential there is no movement of vapor to the radiators. Now we fire the boiler and the water temperature increases. Correspondingly the vapor pressure rises at the boiler and vapor begins to flow to the radiators since the vapor pressure is less there because they are at a lower temperature. Now the vapor will condense there, releasing its latent heat raising the radiator temperature until it reaches equilibrium with the boiler again at a higher temperature and vapor pressure.



So in an ideal system with a perfect vacuum, the vents would do nothing. But in a real system with air leaks and less than perfect vacuum, the air vents would still be necessary to release air each cycle and maintain the vacuum at some finite level with some air always remaining.



It is the differential in vapor pressure in the absence of air that causes the movement of vapor to the radiators rather than the vacuum itself.

Rod

Total Vacuum.

I would think that having a system in a sealed complete vacuum might also cause a lot of problems balance wise as the metered venting of air by the radiator vents is what controls the rate of steam entering the radiators.  With no vents, the condensing is what would control the distribution of the steam and therefore the closest and biggest radiators would initially hog all the steam.

- Rod

Rod

Venturi Pump

Ed- Thanks very much for your input on Paul system.. Using the Taco pump to power a jet venturi extractor is brilliant!!  .My only experience has been with air powered units. Do you remember the name or source of the  bronze extractor?   It would be easy enough to build one but I'm a great believer in letting the other guys would out the "bugs". The liquid jet would be a lot quieter than an electric pump plus you wouldn't have the cooling problems.



On the zoning - What ideas do you have on that?

- Rod

Mike Kusiak_2

Exactly

Rod, I think you may have identified the problem of introducing vacuum on a one pipe cycled system.



The carefully calibrated air venting now has no effect on balancing the simultaneous delivery of steam. I believe Ed also mentioned that balance issues had to be dealt with after vacuum was incorporated in his system.



Perhaps with a two pipe system, balance could be more easily achieved with vacuum by using orifices to even out the vapor distribution.

jumper

vacuum one pipe

I agree with Mike's first post. If there's little enough air in the system all the terminal units will fill with warmed vapour as the boiler fires up. Low pressure steam goes at least half mile per minute. Hopefully each radiator will condense steam at a rate proportional to its heating load. So in principle building self balances.

Long Beach Ed

Distribution

We found with our system that the distribution is nearly instantaneous.  Every radiator received steam within 30 seconds of the header receiving steam. 



The problem, if you can call it that, is that steam fully filled every radiator, from end to end within about five minutes if I recall correctly.  So balance, which is conventionally handled by the sizing of air vents, becomes a different animal.  Radiator sizing and boiler cycle times become more important for balance. 



Remember that this is how coal worked.  Generally, every radiator was

filled with steam from end to end, so unless a system was meddled with,

the radiators will be sized properly for the heat load. 



The cycle times were so important, that we experimented with a thermister-type (high limit control) cutoff that would sense when steam was established at the end of the biggest radiator.  Heating timing would then start as in a Heat-timer system.   It all happened in from two to ten minutes of boiler firing. 



You can, of course throttle the air exhaust from each radiator by putting a valve on each return line. 



An ideal system, as I see it would use Pex or copper return lines coming back to a manifold with balancing valves for each return line.  A different manifold would be used for each "zone" with the vacuum supply to each manifold controlled by a zone valve. 



This would permit balance of each radiator as well as zoning of the system. 



Gerry speaks of some water hammer in his experiment; we never had any at all, but as I mentioned, the system we used happened to have textbook-correct piping and sizing.  If we did get hammering, I suppose we'd try to throttle the vacuum to that particular radiator and try to make it go away, or induce vacuum into a part of the main or dry return.  That would be an interesting troubleshooting job and I look forward to hearing more about it, as typical systems have lots of water trapped in their piping and the vacuum would probably move it around and alter its flow.



Another issue was vacuum control.  We installed a Honneywell Vacustat and set it to cut off vacuum at about 5 inches/HG, as the vintage systems worked between 3 and 5" HG.  In our case, we found it wasn't necessary and we operated the vacuum pump continuously while the system fired. 



I suppose with a tight system, you could have a "purge-type" timer that would run the pump for a while after the burner shuts down, but with the rapid cooling of modern boilers, we never pursued this, feeling the heat would all be gone shortly after the cycle ended.   I suppose one could also start the pump in advance of the burner. 



We also put Paul vents at the ends of the mains.  I don't think that was necessary, as the system removes massive volumes of air quickly through the radiators. 



We envisioned a variable vacuum system where we could vary steam temperature using a "Heat timer" type control motor to vary pump run times dependent on outdoor temperatures, but we never pursued it, partly because we never induced a strong enough vacuum to impact steam temperature.  Perhaps this was due to a leaky system or the quality of our pump.  We did little to check the system for leaks and if we did this again we'd make that a priority. 

Dave in QCA

Fantastic Work!

Ed,  Very good work!  Fantastic information!

jumper

call me mickeymouse

Cheapest & easiest way to balance steam is to insulate portion of oversized terminal. Stuff some burlap behind a radiator. Or in inlet of baseboard. You get the idea.



For more professional looking work there's insulating paint for radiators.

Some convectors have venetian blind like mechanisms for inlet dampers.



Advantage of steam is economy & simplicity. If you only add treated water a steam system can be maintenance free forever. Well almost.

ChrisJ

treated water

What kind of treated water?  And what about the fact a 1 pipe system is constantly filled with fresh air?

jumper

re treated water

Chris, I think you missed the point about that hermetic (or almost) system.

Installer sealed all connections against infiltration and evacuated almost all air.

I presume water was distilled or otherwise demineralized, anti-corrosion agent added , and then degassed as it was transferred to heating system.



The idea is that terminals are almost at saturation temperature and that any condensate that didn't drain evaporates when pressure is reduced. Also remember that it's parallel flow even though it's one pipe. Overhead distribution.



Only when pressure was some percentage above saturation, was vacuum re-applied.

ChrisJ

Ah

Jumper your right for some reason I forgot about the vacuum part of the system.

Pumpguy

vacuum pumps

While Dan's TLAOSH doesn't mention it, Nash Jennings liquid ring vacuum pumps were also used as vacuum producers on one pipe Paul systems.  Today's pumps are much smaller but more efficient than those used back in the day.  Currently, 1 hp, 14 cfm is the smallest available although 3/4 hp is a possibility.  If noisy operation is a concern, a muffler can be applied to the exhaust to quiet them down. 



The historic Monadnock Building is downtown Chicago uses one pipe Paul systems for heating.  They have 2 separate systems, each served by their own vacuum pump.



If anyone would like to pursue this idea, feel free to contact me with questions or to discuss details.



Dennis